1. Background of the Invention
The present invention relates to a power generator for use in a wellbore formed in an earth formation. The purpose of such power generator is, for example, to provide electric power to electrical wellbore equipment, to charge a battery for powering such equipment, or to create an electric charge or discharge in or around the wellbore. However, application of a conventional power generator in a wellbores is impractical or impossible in view of the relatively small diameter of the wellbore, particularly in the deeper sections of the wellbore. Furthermore, the installation of temporary power cables in a wellbore is difficult and expensive.
It is an object of the invention to provide a suitable power generator for use in a wellbore formed in an earth formation.
In accordance with the invention there is provided a power generator for use in a wellbore formed in an earth formation, comprising an internal combustion engine having a cylinder and a piston defining a combustion chamber in the cylinder, the engine being arranged to induce a reciprocating movement to the piston relative to the cylinder upon combustion of a combustible gas mixture in the combustion chamber, and a linear electricity generator having a stator and a drive shaft, the generator being arranged to generate electricity upon a reciprocating movement of the drive shaft relative to the stator, wherein the piston is connected to the drive shaft so as to transmit said reciprocating movement of the piston to the drive shaft.
The power generator can have a relatively small diameter so that the generator fits in the wellbore, by virtue of the movement of the piston and the drive shaft being a reciprocating movement.